Babushok D V, Ostertag E M, Kazazian H H
Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6145, USA.
Cell Mol Life Sci. 2007 Mar;64(5):542-54. doi: 10.1007/s00018-006-6453-4.
Comparative genome analyses reveal that most functional domains of human genes have homologs in widely divergent species. These shared functional domains, however, are differentially shuffled among evolutionary lineages to produce an increasing number of domain architectures. Combined with duplication and adaptive evolution, domain shuffling is responsible for the great phenotypic complexity of higher eukaryotes. Although the domain-shuffling hypothesis is generally accepted, determining the molecular mechanisms that lead to domain shuffling and novel gene creation has been challenging, as sequence features accompanying the formation of known genes have been obscured by accumulated mutations. The growing availability of genome sequences and EST databases allows us to study the characteristics of newly emerged genes. Here we review recent genome-wide DNA and EST analyses, and discuss the three major molecular mechanisms of gene formation: (1) atypical spicing, both within and between genes, followed by adaptation, (2) tandem and interspersed segmental duplications, and (3) retrotransposition events.
比较基因组分析表明，人类基因的大多数功能域在广泛不同的物种中都有同源物。然而，这些共享的功能域在进化谱系中以不同方式重新排列，从而产生越来越多的结构域架构。结合基因复制和适应性进化，结构域重排是导致高等真核生物巨大表型复杂性的原因。尽管结构域重排假说已被普遍接受，但确定导致结构域重排和新基因产生的分子机制一直具有挑战性，因为伴随已知基因形成的序列特征已被积累的突变所掩盖。基因组序列和EST数据库的日益丰富使我们能够研究新出现基因的特征。在这里，我们综述了最近全基因组DNA和EST分析，并讨论了基因形成的三种主要分子机制：（1）基因内和基因间的非典型剪接，随后是适应性变化；（2）串联和散布的片段重复；（3）逆转座事件。
